Inversion of shear-wave velocity structure in shallow soil from Rayleigh waves

Based on the relation between shear-wave velocity of medium and phase-velocity of Rayleigh wave in homogenous half-space, the media at all layers in depths affected by surface wave with a certain frequency are homogenized, making it a equivalent homogenous half-space. On the premise of homogenization, a model is used to be forward solution in order to determine the relation between exploration depth and wave length of surface wave. A phase-matched filtering technique is applied to isolate fundamental Rayleigh wave from observed signals. From multi-filtering and superposition processes, the dispersions of fundamental surface wave and group velocity in 5.0-30.0Hz are precisely calculated Using homogenized technique, a primary inversion model is obtained from dispersion curves of phase velocity. The shear-wave velocity structures at all soil layers above 35m are obtained by inversions of dispersions of group velocity. The results show that the inversions are better coincident with data of drills.